The instant invention relates to apparatus for use in gluing operations, especially in the woodworking industry, and more particularly, to a press which is operable for securing a plurality of workpiece elements in pressurized engagement during a gluing operation.
A variety of different apparatuses have been utilized in industries, such as the woodworking industry, for securing workpiece elements in pressurized engagement during gluing operations. For commercial applications, large presses have been utilized which are capable of applying downward pressures to workpiece elements to maintain them in substantially coplanar relation while simultaneously applying pressures thereto to urge them into pressurized engagement. Presses of this type are commonly used for gluing operations in the woodworking industry to secure wood strips together to form solid panels, to glue wood bands to cores, to face-glue flat boards together to form solid posts or panels, and to apply veneers to the edges of cores. A large variety of products have been commonly manufactured utilizing apparatus of this type, including butcher block panels, raised panel doors, and many table tops.
The most common type of press heretofore available for use in securing workpiece elements together during gluing operations comprises a substantially flat bed for receiving a plurality of workpiece elements thereon, a top platen which is hingeably connected to the bed so that it is adjustably positionable in substantially parallel relation thereto, and means for applying downward pressure to the top platen to urge it toward the upper surface of the bed. Apparatus of this type further comprises an abutment or retaining wall along one edge of the bed for laterally retaining workpiece elements thereon, a plurality of removable pusher shoes which are disposed adjacent an edge of the bed which is opposite from the abutment, and means for urging the pusher shoes toward the abutment. In apparatus of this type, the pusher shoes generally comprise stacks of relatively thin removable pusher shoe blocks which are receivable on the bed between the top platen and the bed surface so that when the top platen is in pressurized engagement with workpiece elements on the bed, the pusher shoes can be utilized for applying lateral pressures to the workpiece elements to urge them toward the abutment and thereby urge them into pressurized engagement with each other. The pusher shoes of apparatus of this type are adjustable for various thicknesses by adding or removing pusher shoe blocks. However, for use of apparatus of this type, the pusher shoes must be adjusted for each different operation so that the combined thicknesses of the blocks are slightly less than the thickness of the workpiece elements on the bed to allow the pusher shoes to be received between the top platen and the bed so that they urge the workpiece elements on the bed into pressurized engagement with each other.
Presses of the above type which utilize pusher shoes comprising stacked pusher-shoe blocks have been found to have several disadvantages. First, a large inventory of pusher-shoe blocks must be maintained in order to accommodate workpiece elements of various thicknesses. Further, pusher-shoe blocks are not always exactly the same length, so that often when they are stacked on top of each other they define irregular faces for the workpiece elements, which causes the workpiece elements to be pressed unevenly when the press is operated. This often causes the workpiece elements to be glued unevenly, which is generally unsatisfactory for all gluing operations, but particularly so when gluing flat boards together to form solid posts or panels or when applying veneers to the edges of cores. Another disadvantage of presses of the above type is that they require substantial amounts of time to adjust the pusher shoes thereof to accommodate workpiece elements of different thicknesses. Further, it has been found that because the addition or removal of pusher-shoe blocks to adjust a press for workpiece elements of different thicknesses is a relatively time consuming operation, it is frequently forgotten or neglected by operators so that presses are frequently operated with incorrect pusher-shoe thicknesses, and this can also cause uneven pressing.
The press of the instant invention has been developed to overcome the disadvantages of the heretofore-known pressing apparatus, and it generally comprises a bed having a substantially flat bed surface thereon, a plurality of spaced pusher shoes disposed adjacent a first edge of the bed, and means for urging the pusher shoes toward an opposite second edge of the bed. The apparatus further comprises means for laterally retaining workpiece elements on the bed surface against movement toward the second edge of the bed, a top platen which has a substantially flat platen surface thereon and which is positionable so that the platen surface is in substantially parallel face-to-face relation with the bed surface, and means for urging the top platen toward the bed. In contrast to the heretofore-known pressing apparatus, however, the top platen of the press of the instant invention comprises a main portion and a plurality of spaced, substantially parallel platen fingers which extend from an edge of the main portion and which are oriented for receiving the pusher shoes of the press therebetween. The platen surface extends across both the main portion and the platen fingers, and hence both the main portion and the fingers are operative for applying pressures to workpiece elements on the bed surface to urge them toward the bed. In further contrast to the heretofore known presses, the pusher shoes, which are preferably permanently attached to the pusher-shoe urging means, travel between the platen fingers rather than between the platen surface and the bed surface. Hence, the pusher shoes are preferably dimensioned to accommodate workpiece elements having thicknesses which are at least equal to the maximum thickness for which the apparatus is intended, although because the pusher shoes travel between the fingers, the same pusher shoes can also be utilized without adjustments thereto for pressing workpiece elements having smaller thicknesses.
Accordingly, because the apparatus of the instant invention comprises pusher shoes which travel between platen fingers so that they are operative with workpiece elements of various thicknesses, many of the disadvantages of the heretofore-known presses are overcome. Specifically, there is no necessity for maintaining a large inventory of removable pusher-shoe blocks, and the necessity for adjusting the thicknesses of the pusher shoes each time workpiece elements of a different thickness are pressed in the apparatus is eliminated. Further, the pusher shoes always provide even, flat working faces which are engageable with workpiece elements to apply even pressure thereto. As a result of these improvements, the chances for operator error are substantially reduced so that the frequency of producing improperly glued workpiece elements is substantially reduced. In addition, since operators are not required to change pusher-shoe blocks to accommodate workpiece elements of different thicknesses, substantial savings in time are realized when operating the apparatus of the instant invention. Hence, it is seen that the apparatus of the instant invention is capable of producing better-quality products at increased production rates, and therefore the apparatus of the instant invention represents a significant advancement in the art.
Accordingly, it is a primary object of the instant invention to provide a pressing apparatus comprising a bed, a top platen, and a plurality of pusher shoes, wherein the pusher shoes are receivable between platen fingers of the top platen for urging workpiece elements into pressurized engagement with each other.
Another object of the instant invention is to provide an improved apparatus for securing workpiece elements in substantially coplanar, side-by-side pressurized engagement during a gluing operation.
A still further object of the instant invention is to provide an apparatus for securing workpiece elements during a gluing operation wherein the addition or removal of pusher-shoe blocks is not required to accommodate workpiece elements of a different thickness in the apparatus.
An even further object of the instant invention is to provide a press for securing workpiece elements in pressurized engagement during a gluing operation which operates with improved accuracy and efficiency and with reduced setup time.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.